The present invention relates to a method for drawing flexible printing blocks onto printing rollers in a registered manner, and to an apparatus for performing the method.
German Pat. No. 818,807 discloses an apparatus for accurately placing printing plates made from rubber or the like on plate mounting bases. Individual flexible blocks are fixed to a flexible packing sheet, by being positioned on a working plate with the aid of thumbtack-like register pins. The packing sheets are then fixed to one side of the printing roller by means of screws and are adhered over their entire area.
Although this apparatus makes it possible to apply individual blocks in an in register manner with the aid of the auxiliary device, it requires the application of two layers (block and packing sheet) to the printing roller. In addition, the problem still exists of applying the packing sheet in registered manner to the printing roller, which must take place very accurately, particularly in the case of several successively operated printing rollers printing the same paper, e.g. for multicolour printing. Furthermore, considerable difficulties are encountered when replacing individual blocks, e.g. in the case of damage, but also when setting up, e.g. in the case of a too bold impression of an individual block. In addition, German Pat. No. 1,132,154, DAS 1,611,388 and DOS 2,256,952 disclose mounting devices, on which blocks are aligned in accordance with layer lines, measuring scales or register crosses and then applied to the printing roller. However, these mounting devices are very complicated mechanical precision devices, which make the complete installation expensive and can only be economically used in large printing works.